JP2009155504A - Matte adhesive tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a matte adhesive tape having low glossiness and suppressed visual glare. <P>SOLUTION: The adhesive tape is provided with an adhesive layer having an uneven surface. The glare of the surface of the adhesive layer due to the reflection of light is reduced by making the adhesive layer dark-colored, and arranging holes having 20-60 μm maximum depth and 30-200 μm maximum width with a fixed interval to be apart from each other on the uneven surface having 0.5-2.5 μm center line average surface roughness. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a matte pressure-sensitive adhesive tape that is useful for fixing an opened member such as a punching sheet where the surface of the pressure-sensitive adhesive tape is visually recognized, and has less light reflection and shine on the surface.

  A technique for fixing an exterior material to an adherend via an adhesive is widely used as a technique for easily imparting desired design properties to the adherend. For example, a decorative sheet in which an adhesive layer is provided on a punching sheet having an opening such as a through hole is widely used as an exterior material such as a speaker of a television or an audio device.

  In such a decorative sheet, since the surface of the pressure-sensitive adhesive layer provided on the punching sheet is visually recognized from the through-hole of the punching sheet, the surface of the pressure-sensitive adhesive layer needs to prevent light reflection and hardly cause shine. is there.

  Examples of the tape having an adhesive layer that is laminated on a punching sheet and used for an acoustic product or the like to reduce the reflection of light include an adhesive tape having a thermally active adhesive layer with a surface matte (Patent Document 1) Adhesive tape provided with irregularities with a 10-point average roughness of 10 to 50 μm on the surface (Patent Document 2), or Adhesive tape provided with irregularities on the surface and having a glossiness of 10% or less (Patent Document 3) Etc. are disclosed.

  However, since these adhesive tapes use a heat-sensitive adhesive, a heating process is required when laminating with a punching sheet, so that the process efficiency is low. In addition, the punching sheet is limited to materials that do not undergo dimensional changes such as melting, softening, and shrinkage in the heating process, and the decoration on the punching sheet needs to be processed and printed so that deformation does not occur in the heating process. there were.

  On the other hand, as a tape having an adhesive layer using an adhesive that does not require a heating process, a double-sided adhesive tape having an adhesive layer matte by a release paper having an embossing process is disclosed (patent) Reference 4). However, the matte pressure-sensitive adhesive layer used in conventional adhesive tapes has been reduced in glossiness by gloss meter measurement, but there are some cases where glare is conspicuous by visual observation, and the design is based on further suppression of glare. Improvement of the property was desired.

ACT 7-42287 JP 7-305038 A JP-A-10-292160 JP-A-9-157612

  The problem to be solved by the present invention is to provide a matte adhesive tape that has a low glossiness and suppresses visual glare. Another object of the present invention is to provide a matte pressure-sensitive adhesive tape that is excellent in adhesion to and adherence to an adherend and whose glossiness does not easily decrease over time.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by adjusting the glossiness of the pressure-sensitive adhesive layer surface of the pressure-sensitive adhesive tape and the fine surface shape, and have completed the present invention.

  That is, the present invention is an adhesive tape provided with an adhesive layer having an uneven surface, wherein the adhesive layer is a dark adhesive layer, and the uneven surface has a center line average surface roughness Ra of 0.00. The present invention provides a matte adhesive tape having a surface in which holes having a maximum depth of 20 to 60 μm and a maximum width of 30 to 200 μm are arranged spaced apart from each other at regular intervals on a rough surface of 5 to 2.5 μm. .

  The matte pressure-sensitive adhesive tape of the present invention is excellent in design because it can reduce glare due to light reflection by reducing the glossiness of the surface of the pressure-sensitive adhesive layer and making the surface shape a certain fine uneven shape. For this reason, the surface of the lower layer, including punching sheets with many holes used as exterior materials for various household electrical appliances such as televisions and stereos, and speakers for audio equipment, whose appearance design affects purchasing It is extremely useful for fixing a member in which is visually recognized.

[Adhesive layer]
The matte adhesive tape of the present invention has a dark pressure-sensitive adhesive layer having an uneven surface. The uneven surface has a rough surface with a center line average surface roughness Ra of 0.5 to 2.5 μm, and the rough surface has constant holes with a maximum depth of 20 to 60 μm and a maximum width of 30 to 200 μm. The surfaces are spaced apart from one another at periodic intervals. Since the matte adhesive tape of the present invention has the surface shape, it can be an adhesive tape having a low glossiness even on the surface of an adhesive having a normal glossiness and in which glare is hardly visible.

  As for the rough surface used as the base surface of an adhesive layer, centerline average surface roughness Ra is 0.5-2.5 micrometers, and it is preferable that it is 0.5-2 micrometers. The surface roughness and surface shape such as the center line average surface roughness Ra can be measured by a non-contact type surface roughness measuring instrument using a confocal laser. The numerical value in the present invention is a value defined by the centerline average surface roughness Ra defined in JISB0601 by “Color 3D Laser Microscope / VK-9500” manufactured by KEYENCE using a violet laser (408 nm) as a laser light source. It is. When measuring the centerline average surface roughness of the rough surface of the pressure-sensitive adhesive layer provided with holes, the centerline average surface roughness of the portion not affected by the waviness of the holes formed on the rough surface is measured. It is easily measured by measuring the thickness. Further, when measuring the surface shape such as the center line average surface roughness Ra, at least 2 to 10 pieces are measured at 1 to 50 μm square when observing the surface roughness and about 1 to 50 μm when observing the line roughness. It is preferable to take an average of the measurement results.

  Since the hole formed in the rough surface is a hole penetrating the pressure-sensitive adhesive layer, the base material of the base is visually recognized from the hole, and there is a possibility that the design property is deteriorated. It is preferable to do. The shape of the hole is not particularly limited, and the shape when observed in the vertical direction from the pressure-sensitive adhesive surface is a circular shape, even if the shape is square, rectangular, trapezoidal, pentagonal, hexagonal, etc. Also good. The shape in the depth direction is not particularly limited, and may be a shape that narrows in order toward the bottom surface or a shape in which the uppermost portion of the hole and the bottom surface have substantially the same area. Among these shapes, a shape having a certain area at the bottom of the hole is preferable, and a hole having a cylindrical shape or a rectangular parallelepiped shape is preferable because it is easy to create.

  The maximum depth of the holes formed on the rough surface is 20 to 60 μm, preferably 30 to 50 μm. By providing a hole of the size on the rough surface, the light scattering effect due to the fine unevenness of the rough surface and the light scattering effect due to the large unevenness of the hole are effectively generated, and the surface of the pressure-sensitive adhesive layer is protected. It can suppress suitably. The maximum depth of the hole refers to the depth from the average line of the roughness curve portion that is not affected by the undulation of the hole in the line roughness curve connecting the center points between adjacent holes. For example, in the case of the staggered arrangement and the parallel arrangement, the depth is measured based on the average of the average lines based on the roughness curve connecting the center points between the holes of two to four adjacent holes. .

  The maximum width of the holes formed on the rough surface is 30 to 200 μm, preferably 50 to 150 μm, more preferably 70 to 120 μm. The maximum width refers to the width of the hole when observed in the vertical direction from the surface of the pressure-sensitive adhesive. If the shape is a circle, the diameter is the longest. The maximum distance in the shape, such as the diagonal distance, is measured as the maximum width.

  The holes formed in the rough surface can be suitably suppressed by providing the surface of the pressure-sensitive adhesive layer with visual recognition by being spaced apart from each other at regular intervals and arranged on the rough surface. The periodic structure may be adjusted as appropriate depending on the shape and size of the holes, but it is preferable to arrange the periodic structure with a period in which the distance between the center points between adjacent holes is 40 to 300 μm, and with a period of 60 to 200 μm. More preferably. It is particularly preferable to arrange with a period of 80 to 180 μm. The distance between the center points is the shape of the hole when observed in the vertical direction from the adhesive surface. May be measured with the point as the center point.

  The inter-hole distance between adjacent holes formed on the rough surface is not particularly limited. However, the light scattering effect on the rough surface and the light scattering effect due to the difference in height between the base surface and the hole are preferably generated. Therefore, the distance between the holes is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 30 μm or more. When the boundary between the rough surface and the hole that is the base in each measurement is not clear, a portion having a height of about 5% of the maximum depth from the average line of the rough surface around the hole is determined as the boundary. That's fine.

  Moreover, the periodic arrangement of the holes is not particularly limited as long as it is an arrangement separated from each other at a constant period, but is preferably a parallel arrangement or a staggered arrangement.

  The center line average surface roughness Ra of the uneven surface including the rough surface serving as the base and the holes provided in the rough surface is preferably 5 to 10 μm, and more preferably 5 to 8 μm. The center line average surface roughness Ra is also determined in the same manner as described above. Moreover, it is preferable that the maximum height Rmax of the said uneven | corrugated surface is 20-80 micrometers, and it is especially preferable that it is 30-60 micrometers.

  The pressure-sensitive adhesive layer is a dark pressure-sensitive adhesive layer in order to suppress the glossiness. The dark color can be any dark color such as black, brown, dark blue, etc., as long as it can reduce glossiness and reduce glare on the surface of the adhesive layer, but it is black because it is easy to suppress glossiness. Is preferred.

  Further, the glossiness of the uneven surface of the pressure-sensitive adhesive layer having an uneven surface is preferably 15 or less, more preferably 10 or less, and even more preferably 5 or less. By suppressing glossiness, reflection of light on the surface of the pressure-sensitive adhesive layer is suppressed, and reflection of light can be reduced even when bonded to a member with a visible surface of the pressure-sensitive adhesive layer such as a punching sheet, preventing deterioration in design. it can.

  As the pressure-sensitive adhesive layer having an uneven surface, a layer made of an acrylic pressure-sensitive adhesive composition containing an acrylic copolymer and a crosslinking agent can be preferably used.

  An acrylic copolymer of an acrylic pressure-sensitive adhesive composition (hereinafter referred to as an acrylic pressure-sensitive adhesive composition (a)) used for a pressure-sensitive adhesive layer having an uneven surface is obtained by using n-butyl acrylate as a main monomer component. Excellent adhesion to punching sheet. As monomer components other than n-butyl acrylate, various monomers can be used. For example, sec-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate , Isononyl acrylate, isodecyl acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, n -Octyl methacrylate, isooctyl methacrylate, 2-ethylhexyl methacrylate DOO, isononyl methacrylate, isodecyl methacrylate, lauryl methacrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate. One or more of these are used.

  In addition, it is preferable to use a carboxyl group-containing monomer in combination, for example, (meth) acrylic acid, acrylic acid dimer, itaconic acid, crotonic acid, maleic acid, maleic anhydride, etc. can be used. Acrylic acid is particularly preferred.

  Furthermore, it is also preferable to use a hydroxyl group-containing monomer in combination, for example, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, etc. can be used. 2-hydroxyethyl acrylate or 4-hydroxybutyl acrylate is preferred.

  As a preferable formulation of the acrylic copolymer used for the acrylic pressure-sensitive adhesive composition (a), the content of n-butyl acrylate is preferably 90 to 97 parts by mass in 100 parts by mass of all monomer components. Moreover, when using a carboxyl group-containing monomer, it is preferable that the content shall be 1-6 mass parts, and when using a hydroxyl-containing monomer, the content is 0.05-0.3 mass. Part.

  By including a cross-linking agent in the acrylic pressure-sensitive adhesive composition (a), the cross-linking system of the pressure-sensitive adhesive layer is adjusted, good rebound resistance, suppression of decrease in gloss, or prevention of pressure-sensitive adhesive leaching, etc. The effect of can be realized. The crosslinking agent used is preferably an isocyanate-based crosslinking agent or an epoxy crosslinking agent.

  As the isocyanate-based crosslinking agent, a toluene diisocyanate adduct can be preferably used. Here, the toluene diisocyanate adduct refers to one containing a toluene diisocyanate derivative in the molecule. Specific examples include Coronate L (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.).

  Examples of the epoxy crosslinking agent include Tetrad X and Tetrad C manufactured by Mitsubishi Gas Chemical Co., Ltd., and E-05X manufactured by Soken Chemical Co., Ltd.

  The content of the crosslinking agent is not particularly limited as long as the gel fraction and the adhesive strength of the pressure-sensitive adhesive layer can be suitably adjusted. In the case of an isocyanate-based crosslinking agent, the content of the crosslinking agent is 2.5 with respect to 100 parts by mass of the acrylic copolymer. It is preferable that it is -5 mass parts, and it is especially preferable that it is 2.5-4 mass parts. When using an epoxy crosslinking agent, it is preferable that it is 0.01-0.05 mass part with respect to 100 mass parts of acrylic copolymers, and it is further 0.013-0.04 mass part. Preferably, it is 0.016-0.037 mass part.

  In the case of an isocyanate crosslinking agent, the gel fraction of the pressure-sensitive adhesive layer is preferably 40 to 80%, and more preferably 45 to 70%. In this case, it is preferable to use a tackifier resin together because the adhesive force can be improved. On the other hand, in the case of an epoxy crosslinking agent, it is preferably 50 to 80%, and more preferably 60 to 70%. By setting the gel fraction of the pressure-sensitive adhesive layer within the above range, the uneven surface can be suitably retained, and an excellent glare-preventing effect can be retained for a long period of time, and can contribute to suitable adhesiveness with the punching sheet. The gel fraction is expressed as a percentage of the original mass by immersing the composition of the double-sided pressure-sensitive adhesive sheet after curing in toluene and measuring the mass after drying of the insoluble matter remaining after standing for 24 hours.

  When the tackifying resin is used in the acrylic pressure-sensitive adhesive composition (a), for example, rosin-based resins such as rosin and rosin esterified products, terpene-based polymers such as diterpene polymers and α-pinene-phenol copolymers. Resins, petroleum resins such as aliphatic (C5) and aromatic (C9), and other tackifying resins such as styrene resins, phenol resins, and xylene resins can be used. Especially, what contains 75-85 mass parts of polymerized rosin and hydrogenated rosin, and 15-25 mass parts of petroleum resins in 100 mass parts of tackifying resin is preferable. Further, the polymerized rosin and the hydrogenated rosin are preferably contained in equal amounts. In 100 parts by mass of the tackifier resin, the polymerized rosin is 40 parts by mass, the hydrogenated rosin is 40 parts by mass, and the petroleum resin is 20 parts by mass. Partly contained is particularly preferred. Specific examples of the polymerized rosin include licarodine PCJ (trade name, manufactured by Rika Hercules Co., Ltd.). Specific examples of the hydrogenated rosin include Superester A100 (trade name, manufactured by Arakawa Chemical Industries, Ltd.). Specific examples of the petroleum resin include FTR-6100 (trade name, manufactured by Mitsui Chemicals, Inc.). By using the tackifying resin having such a preferable composition, the followability of the double-sided PSA sheet to the adherend becomes better.

  It is preferable to contain 20-35 mass parts of tackifying resin with respect to 100 mass parts of acrylic copolymers in an acrylic adhesive composition (a).

  In order to make the pressure-sensitive adhesive layer dark and suppress glossiness, the acrylic pressure-sensitive adhesive composition (a) contains a colorant. Although various dyes and pigments can be used as the colorant, it is preferable to use carbon black, and the amount used is 0.5 to 3 with respect to 100 parts by mass of the acrylic copolymer in the acrylic pressure-sensitive adhesive. It is preferable to set it as a mass part, and it is preferable to set it as the range of 0.66-1.97 mass parts.

  In addition to the components described above, the pressure-sensitive adhesive layer has various additives generally used for pressure-sensitive adhesives, such as antioxidants, ultraviolet absorbers, dispersants, and fillers, as long as the effects of the present invention are not impaired. , Pigments, thickeners, plasticizers, softeners, flame retardants and the like may be contained.

[Matte adhesive tape]
The matte adhesive tape of this invention is an adhesive tape provided with the adhesive layer which has the said uneven surface as an adhesive layer. The configuration of the pressure-sensitive adhesive tape of the present invention may be a pressure-sensitive adhesive tape provided with a pressure-sensitive adhesive layer on one side, or a double-sided pressure-sensitive adhesive tape provided with a pressure-sensitive adhesive layer on both sides, depending on the application to be used. What is necessary is just to select suitably. A double-sided pressure-sensitive adhesive sheet can be suitably used when a punching sheet provided with a large number of holes used as an exterior material for various home appliances and speakers of audio equipment is fixed to a housing.

  The matte adhesive tape of the present invention may or may not be provided with a base material. A structure without a substrate is superior in thickness reduction, and a structure with a substrate is preferably used because of excellent removability from a punching sheet or an adherend.

The substrate to be used is not particularly limited, but a fibrous support such as a non-woven fabric can be preferably used because it has low elasticity and is difficult to reduce the followability to the adherend of the decorative sheet, adhesion, etc. , Pulp, cotton, hemp, rayon and other materials. The basis weight of the fibrous support is preferably 13 to 20 g / m ² .

  The thickness of the matte adhesive tape of the present invention is preferably 0.06 to 0.18 mm, more preferably 0.1 to 0.15 mm, and preferably 0.125 to 0.14 mm. Particularly preferred. By setting the thickness within the range, it is possible to sufficiently ensure the resilience and adhesion to the adherend and to achieve an excellent glare-preventing effect and suppression of gloss.

  When the matte pressure-sensitive adhesive tape of the present invention is a double-sided pressure-sensitive adhesive tape, one of the pressure-sensitive adhesive layers is a matte pressure-sensitive adhesive layer having the uneven surface, and the other side of the pressure-sensitive adhesive layer is a smooth pressure-sensitive adhesive layer. Is also preferable. The double-sided pressure-sensitive adhesive tape having such a configuration is advantageous when fixing a member whose surface of the pressure-sensitive adhesive layer is visually recognized and a member that is not visually recognized in bonding with the pressure-sensitive adhesive layer.

  In the case of a double-sided pressure-sensitive adhesive tape having an uneven surface only on one surface, the other adhesive layer having no uneven surface is preferably an adhesive layer that adheres firmly to various members. . As the pressure-sensitive adhesive layer having no unevenness, a layer made of an acrylic pressure-sensitive adhesive composition containing an acrylic copolymer and a crosslinking agent can be preferably used, similarly to the pressure-sensitive adhesive layer having an uneven surface.

  The acrylic pressure-sensitive adhesive composition (hereinafter referred to as acrylic pressure-sensitive adhesive composition (b)) used for the pressure-sensitive adhesive layer having no uneven surface may be appropriately selected according to the intended use. The composition may be the same as or different from the acrylic pressure-sensitive adhesive composition (a). When securing a strong adhesive force with the adherend, or when preventing the adhesive from seeping out from the gaps or the end of the tape when subjected to heavy loads in a high temperature environment Is preferably the following preferable pressure-sensitive adhesive composition.

  As a preferable blend of the acrylic copolymer used in the acrylic pressure-sensitive adhesive composition (b), the content of n-butyl acrylate is preferably 85 to 97 parts by mass in 100 parts by mass of all monomer components, More preferably, it is 90-97 mass parts. Moreover, when using a carboxyl group-containing monomer, it is preferable that the content shall be 1-6 mass parts, and when using a hydroxyl-containing monomer, the content is 0.05-0.3 mass. Part.

  In the acrylic pressure-sensitive adhesive composition (b), the cross-linking agent of the pressure-sensitive adhesive layer is adjusted by adding a cross-linking agent in the same manner as the acrylic pressure-sensitive adhesive composition (a), and good rebound resistance and pressure-sensitive adhesive are obtained. The effect of preventing oozing out can be realized. The adhesive layer may be provided with release paper when the decorative sheet is distributed, but when this release paper is provided with a slit or the like, a particularly suitable adhesive-preventing effect for preventing bleeding is given. Is required.

  The cross-linking agent used in the acrylic pressure-sensitive adhesive composition (b) is not particularly limited as long as the cross-linking system of the pressure-sensitive adhesive layer can be suitably adjusted. Since it can be adjusted, it can be preferably used. The content of the acrylic pressure-sensitive adhesive (b) when it contains an isocyanate-based crosslinking agent is preferably 0.8 to 3 parts by mass with respect to 100 parts by mass of the acrylic copolymer.

  As for the adhesive layer which does not have an uneven | corrugated surface, it is preferable that the gel fraction is 30 to 55%, and it is still more preferable that it is 35 to 50%. In the case where a release paper having a sheet edge and a slit is provided while having a suitable adhesiveness and followability to the adherend by setting the gel fraction of the pressure-sensitive adhesive layer not having an uneven surface to the above range. Oozing out of the adhesive from the slits can be suppressed.

  It is preferable to use a tackifier resin in combination with the acrylic pressure-sensitive adhesive composition (b). The tackifying resin to be used can be the same as that of the acrylic pressure-sensitive adhesive composition (a), and the range that can be preferably used is also the same as described above. It is preferable to contain 20-35 mass parts of tackifying resin with respect to 100 mass parts of acrylic copolymers in an acrylic adhesive composition (b). Thereby, the adhesive layer of the outstanding adhesive force with a to-be-adhered body can be formed, and the seepage of the adhesive of a double-sided adhesive sheet is suppressed more.

  When a substrate is provided, the ratio of the thickness expressed by (thickness of the pressure-sensitive adhesive layer having an uneven surface) / (thickness of the pressure-sensitive adhesive layer having no uneven surface) is 60/40. It is preferably ˜40 / 60, more preferably 55/45 to 45/65. By setting it as such a ratio, followable | trackability to a to-be-adhered body becomes more favorable.

  The pressure-sensitive adhesive layer having a concavo-convex surface is, for example, affixed to a stainless steel plate, folded back 180 ° in the longitudinal direction, pulled at a speed of 300 mm / min, and has an adhesive force of 12.0 (N / 20 mm) or more. Moreover, it is preferable that the same adhesive force of the adhesive layer which does not have an uneven | corrugated surface is 15.0 (N / 20mm) or more.

  In addition, the measurement of the adhesive force was performed as follows. A double-sided pressure-sensitive adhesive sheet is cut into a width of 20 mm, the release paper on the side opposite to the measurement surface is peeled off, and a 25 μm PET film is laminated. Next, the release paper on the measurement surface side was peeled off, and applied to a stainless steel plate having a thickness of 2 mm as an adherend by pressurizing and reciprocating 2 kg roller under conditions of 23 ° C. and 50% relative humidity, and left for 1 hour. Next, the double-sided PSA sheet was folded 180 ° in the longitudinal direction under the above conditions, pulled at a speed of 300 mm / min, and the adhesive strength (N / 20 mm) when peeled from the stainless steel plate was measured.

[Decorative sheet]
The decorative sheet of the present invention is a decorative sheet in which the above-mentioned matte adhesive tape is attached to one side of a punching sheet, and one side of the punching sheet and an adhesive layer having an uneven surface of the matte adhesive tape are attached. Has a structured structure. When the matte pressure-sensitive adhesive tape is a double-sided pressure-sensitive adhesive tape, as shown in FIG. 1, the adhesive sheet is provided on the other surface of the pressure-sensitive adhesive layer having an uneven surface to be attached to the punching sheet. Can be easily fixed to the body.

  By sticking the adhesive layer having the concavo-convex surface of the matte adhesive tape to the punching sheet, the surface of the adhesive layer visually recognized from the through-hole of the punching sheet becomes the surface of the adhesive layer having a specific concavo-convex, and the through-hole Can prevent shine and glare from

(Punching sheet)
The punching sheet used in the present invention is not particularly limited as long as it is in the form of a sheet provided with a large number of fine through-holes, and examples thereof include various resins or metals. Among these, considering the followability to the adherend, cost, etc., it is preferably made of resin. Specific examples of the resin in this case include polyester, polyvinyl chloride, polystyrene, ABS, polycarbonate / ABS resin and the like, and polyester, polystyrene, and polycarbonate / ABS are particularly preferable. These resins may contain additives such as an antioxidant or an antistatic agent as necessary.

  The shape of the through hole of the punching sheet is not particularly limited, and the shape visually recognized from the surface may be any shape such as a circle, a triangle, a quadrangle, a hexagon, etc., but may be a circle for ease of processing. preferable. Moreover, if the magnitude | size is circular, the diameter is preferable, and if it is various squares, it is preferable that the maximum width is 0.3-1.2 mm. Moreover, it is preferable that a hole area rate is 30 to 50%. Those satisfying these conditions increase the effect of preventing the adhesive from seeping out from the through-hole.

  Moreover, in order to improve the designability, the surface of the punching sheet may be subjected to various surface treatments. For example, the punching sheet surface may be subjected to surface processing having a fine uneven shape so as to have a metallic tone.

  The punching sheet may have a configuration in which ridges are provided on the back surface in order to adjust the glossiness. The wrinkles to be used are those that can suitably suppress light reflection from the through-holes of the punching sheet when laminated with the double-sided pressure-sensitive adhesive sheet, and may be any one that does not significantly reduce the adhesive strength. Examples that can be suitably used include a dust-proof net for speakers made by Sony Chemical, SP7600, and the like.

(Release paper)
When a double-sided pressure-sensitive adhesive tape is used as the matte pressure-sensitive adhesive tape, a release paper layer may be provided on the surface of the pressure-sensitive adhesive layer on the other side of the pressure-sensitive adhesive layer to be attached to the punching sheet. In the distribution process, a structure having release paper can be preferably used. A conventionally well-known thing can be used as a release paper. For example, polyethylene laminated on any of high-quality paper, kraft paper, glassine paper, and kurpack paper, and a release treatment applied thereto, or synthetic resin films such as polyethylene, polypropylene, polyethylene terephthalate (PET) The thing etc. which performed the mold release process on the top are mentioned. Among these, from the viewpoint of productivity and pasting workability, it is preferable to laminate polyethylene on any of high-quality paper, kraft paper, glassine paper, and kurpack paper, and then perform release treatment thereon. Examples of the mold release treatment include conventionally known silicone treatment, long-chain alkyl treatment, fluorine treatment and the like, and silicone treatment is preferable. The thickness of the release paper is preferably 0.05 to 0.2 mm.

  The release paper is preferably provided with a slit from the viewpoint of workability. When fixing the decorative sheet to the adherend by providing a slit, some of the release paper is removed, and the decorative sheet is temporarily fixed to the adherend, and the decorative sheet is positioned easily and precisely. Can be fixed to the adherend. The number, shape, and size of the slits may be appropriately selected according to the purpose. And a slit should just be provided by a conventionally well-known method.

(Adherent)
In the decorative sheet of the present invention, the material of the adherend to be fixed is not particularly limited, but resins such as polystyrene, ABS, polypropylene, and PC / ABS are suitable.

(Form of decorative sheet)
The form of the decorative sheet of the present invention is not particularly limited, and may be, for example, a sheet or roll product form.

(Manufacturing method of decorative sheet)
The decorative sheet of the present invention can be formed by preparing the matte adhesive tape and laminating it with a punching sheet.

  In order to form a matte adhesive tape, an adhesive composition may be prepared and used for coating. An example of manufacturing a decorative sheet when the matte adhesive tape is a double-sided adhesive tape is shown below.

  According to a conventionally known method, for example, an acrylic copolymer is synthesized using a predetermined amount of a predetermined raw material monomer in an organic solvent. The organic solvent is not particularly limited as long as the compounding component to be used is dissolved and does not react with the functional group of the crosslinking agent. For example, ethyl acetate, toluene, xylene, n-hexane, acetone, methyl ethyl ketone Etc. can be used alone or in combination. Of these, ethyl acetate, n-hexane, acetone, and methyl ethyl ketone are preferable. Next, a predetermined amount of tackifying resin is added to the obtained acrylic copolymer solution and mixed uniformly to obtain a pressure-sensitive adhesive solution. Furthermore, a pressure-sensitive adhesive composition is obtained by adding a predetermined amount of a cross-linking agent to the obtained pressure-sensitive adhesive solution and stirring it. The pressure-sensitive adhesive composition may be further diluted with an organic solvent such as toluene or hexane as necessary.

In addition, it is preferable to use ethyl acetate and methyl ethyl ketone alone or in combination as an organic solvent in the synthesis of the detolueneized acrylic copolymer. Furthermore, a detolueneized pressure-sensitive adhesive composition can be obtained by adding a predetermined amount of a detolueneized crosslinking agent to the obtained pressure-sensitive adhesive solution and stirring the mixture. The pressure-sensitive adhesive composition may be further diluted with an organic solvent such as ethyl acetate, methyl ethyl ketone, hexane or the like, if necessary. As a result, a matte adhesive tape having a toluene content of 1 μg / cm ² or less can be formed.

  The matte pressure-sensitive adhesive tape used in the present invention has a pressure-sensitive adhesive layer on the surface in contact with the punching sheet, and the pressure-sensitive adhesive layer is a mat separator mat such as release paper or release film whose surface is matted. It can be formed by applying a pressure-sensitive adhesive composition to the surface and drying it, and then peeling off the mat separator.

  The mat separator that can be used here may be any as long as it can form the concavo-convex shape described above on the surface of the pressure-sensitive adhesive layer, and examples thereof include “WHKR-78FNR Kai” manufactured by Lintec Corporation.

  The manufacture of the matte pressure-sensitive adhesive tape having the pressure-sensitive adhesive layer on both sides can be exemplified by the following method when the base material is not provided. Apply the pressure-sensitive adhesive composition onto the release surface of the mat separator using a roll coater or die coater, etc., and dry it so that it has a predetermined thickness after drying. It can be produced by applying and drying the pressure-sensitive adhesive composition and laminating them so that the pressure-sensitive adhesive layer appears. On the other hand, when the double-sided pressure-sensitive adhesive sheet has a double-sided pressure-sensitive adhesive tape structure having a base material as a core, in order to impregnate the pressure-sensitive adhesive composition up to the inside of the support, the pressure-sensitive adhesive composition is one of the supports. It is applied directly to the surface, the organic solvent is dried, and a pressure-sensitive adhesive layer having a predetermined thickness is formed on a support impregnated with pressure-sensitive adhesive. Then, a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer separately formed on the mat separator is laminated on the surface of the support on which the pressure-sensitive adhesive layer is not formed, to produce a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on both sides of the substrate. it can. Alternatively, a pressure-sensitive adhesive composition coated on a mat separator and dried may be prepared, and a dried product coated on another release paper and prepared by thermal lamination on both sides of the substrate. Good.

  The decorative sheet of the present invention can be produced by peeling off the mat separator from the matte adhesive tape obtained as described above, and bonding the adhesive layer obtained by peeling off the mat separator to the punching sheet. At this time, if necessary, the double-sided pressure-sensitive adhesive sheet may be bonded to the surface of the punched sheet on which the rivets are laminated.

  The decorative sheet of the present invention has an excellent design property because it can reduce the glossiness of the surface of the pressure-sensitive adhesive layer visually recognized from the through-hole of the punching sheet and can reduce glare due to reflection of light. Moreover, the outstanding adhesiveness, shape followable | trackability, or resilience resistance can be implement | achieved, and the oozing-out suppression of an adhesive can also be provided. Furthermore, since the configuration is simple, it can be manufactured at low cost.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.

<Preparation of pressure-sensitive adhesive composition (a)>
In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas inlet, 93.4 parts by weight of butyl acrylate, 3 parts by weight of vinyl acetate, 3.5 parts by weight of acrylic acid and 0.1% of hydroxyethyl acrylate Part by mass and 0.2 part by mass of 2,2′-azobisisobutylnitrile as a polymerization initiator are dissolved in 50 parts by mass of ethyl acetate and 20 parts by mass of toluene, and polymerized at 70 ° C. for 8 hours. A coalesced solution was obtained.

  In the acrylic copolymer solution, 11.52 parts by mass of Licarodin PCJ (trade name, manufactured by Rika Hercules Co., Ltd.) and Superester A100 (trade name, manufactured by Arakawa Chemical Industries, Ltd.) with respect to 100 parts by mass of the acrylic copolymer. ) 11.52 parts by mass and 5.76 parts by mass of FTR-6100 (trade name, manufactured by Mitsui Chemicals, Inc.) were added and diluted and mixed with ethyl acetate to obtain an adhesive solution. Into the obtained adhesive solution, an isocyanate-based crosslinking agent (“Bernock NC-40” manufactured by Dainippon Ink & Chemicals, Inc., solid content 40% by mass, ethyl acetate solution) is added to 100 parts by mass of the acrylic copolymer. Add 3.0 parts by weight of carbon black black pigment paste ("DICTON AR8555 black" manufactured by Dainippon Ink and Chemicals, solid content of 49% by mass) to a solid content of 2.0 parts by mass and stir. The pressure-sensitive adhesive composition (a) was prepared.

<Preparation of pressure-sensitive adhesive composition (b)>
In the acrylic copolymer solution obtained above, an isocyanate-based crosslinking agent (“Bernock NC-40” manufactured by Dainippon Ink & Chemicals, Inc., solid content 40% by mass, ethyl acetate with respect to 100 parts by mass of the acrylic copolymer. A pressure-sensitive adhesive composition (b) was prepared in the same manner as the pressure-sensitive adhesive composition (a) except that the solution was added so that the solid content was 1.5 parts by mass.

<Preparation of pressure-sensitive adhesive composition (c)>
Using a reaction vessel equipped with a stirrer, reflux condenser, thermometer, dropping funnel and nitrogen gas inlet, 89.9 parts by mass of butyl acrylate, 10.0 parts by mass of acrylic acid, 0.1 mass of 4-hydroxybutyl acrylate Part and 0.03 part by mass of 2,2-azobisisonitri as a polymerization initiator were dissolved in a mixed solvent consisting of 63 parts by mass of ethyl acetate and 100 parts by mass of acetone. Subsequently, it superposes | polymerizes at 65 degreeC for 6 hours, 0.2 mass part of additional 2, 2- azobis isobutyl nitriles and 45 mass parts of ethyl acetate are added to this, and also it superposes | polymerizes for 6 hours, The mass mean molecular weight 900,000 (polystyrene (Converted) acrylic copolymer solution. Ethyl acetate was added to this acrylic copolymer solution to obtain an acrylic copolymer solution having a nonvolatile content of 30% by mass.

  To the acrylic copolymer solution obtained above with respect to 100 parts by mass of the acrylic copolymer, an epoxy crosslinking agent (“E-05X” manufactured by Soken Chemical Co., Ltd., solid content: 0.5% by mass) 0.037 parts by mass, carbon black black pigment paste ("DICTON AR8555 black" manufactured by Dainippon Ink & Chemicals, Inc., solid content 49% by mass) was added to a solid content of 2.0 parts by mass and stirred. The pressure-sensitive adhesive composition (c) was adjusted.

<Preparation of pressure-sensitive adhesive composition (d)>
An epoxy-based crosslinking agent (“E-05X” manufactured by Soken Chemical Co., Ltd., solid content: 0.5% by mass) is added to an acrylic copolymer solution with respect to 100 parts by mass of the acrylic copolymer, and the solid content is 0.018 mass. The adhesive composition (d) was prepared in the same manner as the adhesive composition (c) except that it was added so as to be part.

Example 1
The pressure-sensitive adhesive composition (a) was matte-polyethylene laminated on one side of a high-quality paper, and the release treatment was performed on a 0.125 mm-thick double-sided polyethylene laminate release paper “WHKR-78FNR Kai” on a mat separator made by Lintec Corporation. Then, coating was performed so that the thickness after drying was 60 μm, and drying was performed at 90 ° C. for 2 minutes to prepare an adhesive layer (A). The pressure-sensitive adhesive composition (b) was dried on 0.13 mm thick release paper “CW73 Cha PL (31) TP25” (manufactured by Lintec Corporation) obtained by releasing a double-sided polyethylene laminate on fine paper. The film was applied so that the subsequent thickness was 65 μm, and dried at 90 ° C. for 2 minutes to prepare an adhesive layer (B). The obtained pressure-sensitive adhesive layer (A) and pressure-sensitive adhesive layer (B) were each transferred to a nonwoven fabric having a basis weight of 17 g / m ² made of a mixed material of pulp, hemp and rayon (manufactured by Nippon Daishowa Paperboard Co., Ltd.). The laminate was applied with a pressure of 4 kgf / cm with a hot roll at 0 ° C., and was aged in an oven at 40 ° C. for 2 days to obtain a double-sided PSA sheet (1). The gel fraction of the pressure-sensitive adhesive layer (A) of the obtained double-sided pressure-sensitive adhesive sheet (1) was 55%, and the gel fraction of the pressure-sensitive adhesive layer (B) was 45%.

  The mat separator was peeled off from the double-sided pressure-sensitive adhesive sheet (1) obtained above, and the exposed uneven surface of the pressure-sensitive adhesive layer (A) had a through-hole diameter of 0.35 mm, a hole area ratio of 42%, a thickness of 0. A decorative sheet (1) was obtained by bonding to the surface of a 4 mm polystyrene punching sheet.

(Example 2)
Except that the adhesive composition (c) was used instead of the adhesive composition (a) used in Example 1 and the adhesive composition (d) was used instead of the adhesive composition (b), the same as Example 1 was used. Thus, a decorative sheet (2) was obtained.

(Example 3)
Instead of the mat separator “WHKR-78FNR modified” used in Example 1, the embossing has convex portions arranged in parallel, and the embossing has a distance between center points of adjacent convex portions of about 140 μm and a period. The same as in Example 1 except that a polypropylene laminate release paper having a convex shape observed from the surface of the paper having a square shape of about 60 μm on each side and a convex shape observed from the side surface having a trapezoidal shape having a maximum height of about 40 μm was used. Thus, a decorative sheet (3) was obtained.

(Comparative Example 1)
Instead of the mat separator “WHKR-78FNR modified” used in Example 1, a glossy surface separator “KPP-78 Shiro (35-HO)” manufactured by Lintec Co., Ltd. was used. A decorative sheet (H1) was obtained.

(Comparative Example 2)
A decorative sheet (H2) was prepared in the same manner as in Example 1 except that instead of the mat separator “WHKR-78FNR Kai” used in Example 1, a mat separator “I mat” manufactured by Goyo Paper Industries Co., Ltd. was used. Obtained.

<Test method>
The following evaluation was performed about the obtained double-sided adhesive sheet and the decorative sheet. The obtained result is shown to Tables 1-2.

(1) Glossiness measurement The uneven | corrugated surface of the adhesive layer (A) before bonding with a punching sheet was measured by the method prescribed | regulated to 60 degree specular glossiness and JISZ-8741. As a measuring apparatus, “Multi-Gloss 268” manufactured by MINORUTA was used. The glossiness after the high temperature test was measured after the uneven surface of the pressure-sensitive adhesive layer (A) was left at 60 ° C. for 30 days.

(2) Surface shape measurement The surface of the pressure-sensitive adhesive layer (A) before being bonded to the punching sheet was measured using a “Color 3D Laser Microscope / VK-9500” manufactured by KEYENCE, with a lens magnification of 50 times and a measurement mode exceeding Depth, pitch is 0.05 μm, optical zoom is 1.0 times, 200 × 250 μm square surface measurement is performed at any three locations, center line average surface roughness Ra of the rough surface, maximum hole depth, The maximum width and the distance between the center points were measured. In addition, for the centerline average surface roughness Ra of the rough surface, the surface roughness of 50 μm square is measured for any three points not affected by the waviness of the holes between the holes for each surface measurement. The average value of the measurement is shown in the table as the center line average surface roughness Ra. About the maximum depth of a hole, the maximum width, and the distance between center points, it confirmed about all the holes (2-4 pieces) which can be confirmed in each surface measurement, and showed the average value in the table | surface, respectively. In addition, the periodic arrangement of the holes and the shape of the holes visually recognized from the pressure-sensitive adhesive layer surface are shown in the table.

(3) Light reflectivity (visual)
The shine and glare from the through-hole on the punching sheet surface of the decorative sheet cut to a size of 20 mm × 90 mm were visually observed under a fluorescent lamp from a direction perpendicular to the punching sheet surface. Evaluation based on the following criteria for the visual observation was performed on five subjects.
5: The shine and glare are not visually recognized 4: The shine and glare are hardly visually recognized 3: The shine and glare are visually recognized, but the design is not impaired. 1: shine and glare are visually recognized, and the design is greatly impaired

(4) Resilience Release paper was peeled from the decorative sheet cut to a size of 20 mm × 180 mm, and fixed to the center of a polystyrene plate having a thickness of 2 mm, a width of 25 mm × a length of 200 mm, which is an adherend. Next, the polystyrene plate on which the decorative sheet was fixed was fixed in a bow with a length of 190 mm along the longitudinal direction so that the decorative sheet was convex, and this state was maintained at 80 ° C. for 96 hours. And the presence or absence of peeling between the punching sheet / decorative sheet after 96 hours and the peeling of the decorative sheet from the polystyrene plate was evaluated.
The evaluation criteria for the resilience test results are as follows.
○: Peeling between punching sheet / decorative sheet, no peeling from polystyrene plate ×: Peeling between punching sheet / decorative sheet, or peeling from polystyrene plate

(5) Polystyrene adhesive strength The decorative sheet is cut to a width of 20 mm, the release paper is peeled off, and the thickness of the adherend is 2 mm by pressurizing and reciprocating 2 kg rollers at 23 ° C. and a relative humidity of 50%. Attached to a polystyrene (Pst) plate and allowed to stand for 1 hour. Next, the decorative sheet was folded 180 ° in the longitudinal direction under the above conditions, pulled at a speed of 300 mm / min, and the adhesive strength (N / 20 mm) when peeled from the Pst plate was measured.

<Evaluation results>
As is clear from Table 1, it was confirmed that Examples 1 to 3 were hardly visually recognized as surface shine and glare, and had high stability. In Comparative Examples 1 and 2, it was confirmed that the surface shine and glare were both visually recognized and the design properties were impaired. As described above, the decorative sheet of the present invention provided with the double-sided pressure-sensitive adhesive tape having the adhesive of the present invention showed almost no surface shine and glare than the conventional decorative sheet. Further, as is clear from Table 1, it was confirmed that the decorative sheets of Examples 1 to 3 were excellent in followability to the adherend.

It is a cross-sectional schematic diagram which shows an example of the decorative sheet which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Decorative sheet 2 Punching sheet 3 Double-sided adhesive sheet 4 Release paper 31 Adhesive layer 32 Adhesive layer 33 Support

Claims (10)

An adhesive tape provided with an adhesive layer having an uneven surface, wherein the adhesive layer is a dark adhesive layer, and the uneven surface has a center line average surface roughness Ra of 0.5 to 2.5 μm. A matte pressure-sensitive adhesive tape, characterized in that the surface is a surface in which holes having a maximum depth of 20 to 60 μm and a maximum width of 30 to 200 μm are arranged spaced apart from each other at regular intervals. The matte adhesive tape according to claim 1, wherein the distance between the center points between adjacent holes is 40 to 300 µm. The matte adhesive tape according to claim 1 or 2, wherein the uneven surface has a glossiness of 15 or less. The matte adhesive tape according to any one of claims 1 to 3, wherein the uneven surface has a center line average surface roughness Ra of 5 to 10 µm. The pressure-sensitive adhesive layer is composed of an acrylic pressure-sensitive adhesive containing an acrylic copolymer containing n-butyl acrylate as a main monomer component, a tackifier resin and an isocyanate-based crosslinking agent,
The matte pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein a content of the isocyanate-based crosslinking agent is 2.5 to 5 parts by mass with respect to 100 parts by mass of the acrylic copolymer. The pressure-sensitive adhesive layer consists of an acrylic pressure-sensitive adhesive containing an acrylic copolymer containing n-butyl acrylate as a main monomer component and an epoxy-based crosslinking agent,
The decorative sheet according to any one of claims 1 to 4, wherein the content of the epoxy crosslinking agent is 0.001 to 0.05 parts by mass with respect to 100 parts by mass of the acrylic copolymer. The matte adhesive tape according to any one of claims 1 to 6, wherein the array is a parallel array or a staggered array. The matte pressure-sensitive adhesive tape according to any one of claims 1 to 7, wherein a pressure-sensitive adhesive layer having no uneven surface is provided on the other surface of the pressure-sensitive adhesive layer having the uneven surface. A decorative sheet comprising an adhesive layer having an uneven surface of the matte adhesive tape according to any one of claims 1 to 7 attached to one surface of a punching sheet. The decorative sheet according to claim 9, wherein a thickness of the punching sheet is 0.2 to 0.6 mm, and a diameter of a through hole of the punching sheet is 0.3 to 1.2 mm.

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